Annealing



V. B. BROWNE Sept. 1, 1931.

ANNEALING 2 Sheets-Shea?l 1 Original Filed May 28, 1927 2 Sheets-SheetV. B. BROWNE Sept. 1, 1931.

ANNEALING original Filed Maf' 28, 192'? FIG Z.

Vm/07M wwwa@ atentecl Sept. l, 1931 I PATENT OFFICE D'VERE B. BROWNE, 0FBRAC'KENRIDGE, PENNSYLVANIA 'ANNEALING Original application led May 2.8,1927, nSerial No. 194,927. Divided and this application led September26,

1929. Serial No. 395,224.

This invention relates to the manufacture of magnetic alloy sheets andmore particularly to the annealing of relatively thin sheets of siliconiron or so called silicon steel for use in the manufacture of electricalapparatus, and this application is a division of my 'copendingapplication Serial No. 194,927, led May 28, 1927.`

-In the annealing of light gauge silicon iron or so called zsteelsheetsfor use in the manufacture of electrical appara-tus, it has been shownthat if the correct temperature is obtained andthe time of annealing issufficient, better results are obtained by annealingA the sheets singlythan in "stacks as in standard box annealing operation.

Obviously the best results, therefore, should be obtained by annealingin a continuous furnace in which the sheets are charged at one end ofthe' furnace and passed through a correct temperature zone and at a rateof speed such as to give the necessary time element to the annealing.Such a furnace canv be made suiliciently long vto permit a cooling zonevthrough which sheets-pass after they are annealedso that Y neale'd inany of the continuous furnaces withfwhich I am familiar become warped orbuckled and unsuitable for use in the manufacture of electricalapparatus. 'Flatness is most important in sheets for use in themanufactureof electrical apparatus.

It has been found that in orderto obtain magnetic alloy sheetsV ofthehighest qual-- ity it is necessary during the annealing thereof tolprevent the gases given off from the sheets during the anneal frombeing reabsorbed. l

An object Vof this invention is -to provide an apparatus for theannealing of magnetic are subjected to flattening strains of suftionalview, partly broken away, through the "can be employed. The sheets tobeannealed are passed through this .annealing chamber,

alloy sheets by means of which thel-sheets are not only maintained latduring the anneal but are delivered from the anneal fiat and with aminimum amount of occluded gases.

A further object ofthis invention is to provide an apparatus for theannealing of magnetic alloy sheets in whichthe sheets during the annealand subsequent cooling ficient intensi-ty to overcomeV the' distorting60 strains produced-in the Sheets during -rolling and during coolingafter annealing,

A still further objectl of this invention is to provide an apparatus forthe annealing of magnetic alloy sheets in which thorough Ventilation ofthe sheets during annealing and subsequent cooling is obtained wherebythe gases given off from the sheets during `annealing are rapidlycarried out of contact with the sheets. Y

These and other objects which will be apparent to those skilled in thisparticular art are accomplished by means 'of the apparatus illustratedinthe accompanying drawings and described in detailin the specification.In the" drawings, Figure l is a perspective partially broken-away viewof an annealing apparatus embodying one form of this invention, andAFig. 2 is a transverse sec- 80 apparatus illustrated in Fig. 1. n Incarrying out this invention, an annealing chamber of any desired typeorV form or under some circumstances may merely be .positionedtherein,`where they Will be sub-v jected to the annealing temperature'.Each` sheet is so supported as to be separated from every other sheet inthe chamber so that perfect ventilation may be obtained around each ofthe individual sheets. If desired, the sheets may be in groups of'two ormore, as illustrated. In order r'to remove the buckles due to rollingand tor prevent any distortion of the sheets during cooling afterannealing each sheet is subjected ytoan ex ter'nally applied strainwhich places the sheet under-such tension -as -to insure its hold themin flattened condition until their l temperature is lowered to thenecessary point.

'Ihe particular form of apparatus illustrated in the accompanyingdrawings, in-

cludes a furnace formed from a plurality of similar sections 5 havingrecesses G so formed in the inner walls thereof that when two sectionsare positioned opposite to each other the oppositely positioned recessescooperate to provide an annealing chamber 7 having slots 8 and 9extending through the top and bottom, respectively, of the furnace, andcommunicating with the annealing chamber. In the form shown forillustration the furnace is heated by electric resistance elements 10but it will be apparent that any type of heater can be employed. It willalso be apparent that an annealing chamber and furnace of any desiredlength can be provided by associating together a sufficient number ofindividual furnace sections.

Mechanism is provided for passing the sheets to be annealed through theannealing chamber. As illustrated, this mechanism includes a track 11which extends longitudinally above the furnace in line with the slot'8communicating with the upper end of the combustion chamber. Trolleys 12are supported upon the track by rollers 13 and each trolley has a hanger14 secured thereto and extending downwardly below the top of theannealing chamber. Each hanger 14 has a plurality of upwardly inclinedprongs 15. on each side thereof for the purpose of supporting a pair ofsheets 16 to be annealed.

In order to prevent distortion of the sheets during the annealingoperation they are subjected to'stretching or tension of such intensityasto flatten the sheets as they are softened during annealing and tohold them fiat during their passage through the annealing and coolingzone of the chamber. As illustrated, this mechanism includes a track 17which is parallel to the track 11 and is positioned in line with andbelow the channel or slot 9 communicating with the bottom of theannealing chamber. A hanger 18 having sheet engaging lprongs 19 issecured to the lower edges of the sheets 16 and aninverted trolley 20having a roller 21 engaging the bottom of the track 17 is connected tothe inverted hanger 18 by a suitable connection preferably .including aThe springs 22 are of` helical spring 22. such strength that the sheetsstretched thereassises by will be flattened when soft and will be heldtaut and rigid during the entire annealing and cooling operation. Inthis way the buckles and other unevennesses due 'to rolling areobliterated and the buckling during cooling is overcome. rIhe sheets canbe moved through the annealing chamber at the desired rate of speed byshifting the trolleys along the associated tracks.

It will be apparent that the sheets during annealing are perfectlyventilated, thus permitting the free escape of occluded gases.v

rlhis results in finished sheets having extremely low magnetic losses.Absolute Hatness of the finished sheets is insured by positivelymaintaining the sheets taut and rigid during the entire annealing andcooling operation. Gbviously, the sheets can be passed through thefurnace in groups of two, as illustrated, or theyr may be pasted singlytherethrough.

That I claim as new and desire to secure by Letters Patent is:

1. An annealing furnace formed of two oppositely positioned sectionsprovided with recesses in their inner faces cooperating to form anannealing'chamber, said sections being spaced so as to provide slotsextending through the roof and floor of said furnace and communicatingwith said chamber, a track associated with the slot in said roof and atrolley movable along said track and extending into said chamber forsupporting a sheet to be annealed, a second track positioned beneath theslot in said iioor and mechanism movable along said second track andengaging said sheet for applying a stretching force thereto.

2. AnYa-nnealing furnace formed of two oppositely positioned sectionsprovided with recesses in their inner faces cooperating to form anannealing chamber, said sections being spaced so as to provide slotsextending through the roof and floor of said furnace and communicatingwith said chamber, means associated with the slot in said roof forsupporting a sheet to be annealed, and means associated with the slot inthe floor to apply a stretching force to said sheet.

3. An annealing furnace formed of two oppositely positioned sect-ionsprovided with recesses in their inner faces cooperating 'to form anannealing chamber, said sections being spaced so as to provide slotsextending through the roof and floor of said furnace and` communicatingwith said chamber, means associated with each slot to support a sheet tobe annealed in the furnace and apply a stretching force tothe oppositeend of saidsheet.

f 4. An annealing furnace formed of two oppositely positioned sejctionsprovided with recesses in'their inner faces cooperating to form anannealing chamber, said sections being spaced so as to provide slotsextending means for engaging the top of the sheet.

5. An annealing furnace forlned of two oppositely positioned sectionsprovided with recesses in their inner faces cooperating to form anannealing chamber, said sections being spaced so as toprovide slotsextending through the roof and ioor of said furnace and colnmunicatingwith said chamber, means associated with the slot in said roof forsupporting a sheet to be annealed, and means associated with the slot inthe floor to apply a stretching force .-to said sheet, saidl secondmeans including a track, a trolley having a roller engaging said trackfrom below and a` hanger extending into said chamber for engaging thebottom of the sheet, and a spring between said trolley and hanger.

6. An annealing furnace formed of two oppositely positioned sectionsprovided with recesses in their inner faces cooperating to form anannealing chamber, said sections being spaced so as to provide slotsextending through the roof and floor of said fur- .nace andcommunicating with said chamber,

means associated with the slot in said roof for supporting a sheet to beannealed, and means associated with the slot in the floor to apply astretching force to said sheet, said first means including a track, atrolley having a roller engaging on said track and a hanger connected tosaid trolley4 and extending into said chamber provided with means forengaging the top .of the sheet, said second means including aL track, atrolley having a roller engaging said track from below and a hangerextending into said chamber for engaging the bottom ofthe sheet, and aspring between said trolley and hanger.

7. An annealing furnace formed of two oppositely positioned sectionsprovided with recesses in their inner faces cooperating to form anannealing chamber, said sections being spaced so as to provide slotsextending through the roof and floor of said furnace and communicatingwith said chamber, means associated with the slot in said roof forsupporting a sheet to be annealed, and means associated with the slot inthe Hoor to apply a stretching force to said recesses in their innerfaces cooperating to form an annealing chamber, said sections beingspaced so as to provide slots-extending through the roof and floor ofsaid furnace and communicating with said chamber, means associated 'withthe slot in said roof for supporting a sheet to be annealed, and meansassociated with the slot in the fioor to apply a stretching force tosaid sheet, said chamber being of Variable length depending upon thenumber of oppositely associated sections assembled end to end to givethe desired length.

In testimony whereof, I have hereunto subscribed my name this 14th dayof September, 1928.

VERE B. BROVNE.

sheet,-sai d chamber having internal heating means.

8. An annealing furnace formed of two oppositcly posltloncd ser( lonsprovided with

